A Cease and Desist letter, also known as “infringement letter” or “demand letter,” is a document sent to, or delivered to, an individual or business to halt purportedly unlawful activity (“cease”) and not take it up again later (“desist”). It is a written warning requesting a party to stop a specified action, stated in the letter, and not to take it up again. It can be an effective tool to resolve many trademark infringement matters.